Thermostatically-controlled fluid heater



J1me 1929- v. G. VAUGHAN THERMOSTATICALLY CONTROLLED FLUID HEATER FiledOct. 20, 1927 INVENTOR Vz'ctor G. Vaughan.

ATTORNEY Patented June 4, 1929.

UNITED STATES PATENT OFFICE.

VICTOR G. VAUGHAN, OF MANSFIELD, OHIO, ASSIGNOR TO WESTINGHOUSE ELECTRIC& MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

THERMOSTATICALLY-CONTROLLED FLUID HEATER.

Application filed October 20, 1927. Serial No. 227,416.

My invention relates to immersion electric fluid heaters andparticularly to heaters oi the thermostatically controlled type.

An object of my invention is to provldea thermostatically controlledimmersion fluid heater that shall be simple in construction and easilymanufactured.

A further object of my invention is to provide a thermostaticallycontrolled heater that shall be operable to maintain the temperature ofa fluid to be heated thereby substantially constant, and that shall beoperable to protect the heating element from overheating in the eventthat it is not submerged in flui In practicing my invention I provide aclosure member for a conduit, to which a sheathed electric heatingelement is secured in thermal relation therewith. The heating element isadapted to be placed in the conduit and the opening through which it isinserted to be closed by the closure member.

In order'that the heating element may be protected from over-heating,and that the temperature of fluid flowing through the conduit may becontrolled, a thermostatic switch for controlling the heating element ismounted in a cup portion of the closure member.

For a fuller understanding of my invention, reference may be had to thefollowing description, taken in conjunction with the accompanyingdrawings, in which:

' trated in Figs. 1 and 2,

Figure l is a partial view, artially in section, of a fluid tank and a termostatically controlled heating unit for heating fluids stored in thetank,

Fig. 2 is a view, in section, taken on line 11-11 of Fig. 1,

Fig. 3 is an edge view of a switch-supporting member embodied in thedevice illus- Fig. 4 is a view, in section, taken on line IVIVof Fig. 3,and

Fig. 5 is a schematic illustration of the circuit connection of theheating element and the thermostatic switch embodied in the device ofFigs. 1 and 2.

In the drawings, an open-end pipe fitting 1 is illustrated that isprovided with an internally screw-threaded opening 2 that hasscrew-threaded engagement with a pipe 3 extending from the top of a tank4-.

The lower end of the tank is prov ded w th a pipe 5, to the outer end ofwhich a pipe fitting 6 is connected. The lower end of the pipe fitting 6is provided with a plug 7 that has screw-thread engagement with aninternally screw-threaded opening in the bottom thereof through whichfluid may be drained.

The pipe fittings 1 and 6 are connected by a conduit 8 that hasscrew-thread engagement with the adjacent open ends of the fittings.Thus, it is seenthat a passagewa for the circulation of fluid from thetan through the pipe 5, the conduit 8 and the pipe 3 to the upper end ofthe tank 4 is provided.

The upper end of the pipe fitting 1 is provided with a closuremember 9of substantially cup-shape. A gasket'lO is disposed between the rim ofthe closure member 9 and the upper end of the pipe fitting 1, in orderthat a fluid-tight joint may be provided when the closure memberissecured to the pipe fitting by means of bolts 11.

A tubular heating element 12 of substantially hairpin shape is supportedby the closure member 9, the ends of the heating element extendingupwardly through the rim of the closure member and in contact with thesides of the cup portion of the closure member.

The tubular heating element may be secured intimately thereto bybrazing, or, in some instances, the heating element may be cast in theclosure member. As is shown in Fig. 1 of the drawings, the tubularheating element 12 extends downwardly throu h the conduit 8, so that ifthe fluid level in the tank 4 is above the level of the pipe 3, thegeagingelement will be submerged in the In order that the temperature offluid in the tank 4 may be controlled or maintained at a substantiallyconstant value, and in order that the heating element 12 may beprotected from overheating in the event that the water level in the tank4; becomes lower than the level of the pi e 3, a thermostatic switch 13is provided, t e switch being lo- Fig. 5), secured to one face of thebase.

The contacts 15 to 19 may be insulated from the base 14 by a sheet ofinsulation 21. The contaCt l5 and 1. are provided with terminals 22 and23 that are secured on the opposite face of the base 14. Y

The stationary contacts 15 to 19, inclusive, cooperate with relativelymovable contacts or bridging members 24 to 27, inclusive, that arecarried by, a temperature-responsive bimetallic disc 28, but suitablyinsulated therefrom. The disc 28 is secured to the base 14 by anadjustable supporting stud 29.

As is shown in Fig. 5, the discs 24 to 27, inclusive, engage and bridgeadjacent ends of the stationary contact members 15 to 19, inclusive.When the disc 28 is in the position shown in Fig. 1 of the drawings, anelectric circuit may be completed between the terminals 22 and 23 of theswitch.

The switch 13, embodying the bimetallic disc 28, is preferably of thetype disclosed in the U. S. Patent 1,448,240 to J. A. Spencer. The discthere disclosed has the characteristic that, when normally cool, themovable contacts or bridging members 24 to 27, inclusive, engage thestationary contact members 15 to 19, inclusive, but, when heated to atemperature of a predetermined value, the disc suddenly changes itsshape with a snap motion, thereby causing disengagement of the contactmembers. If the disc is subsequently cooled to a lower temperature of apredetermined value, the disc again assumes its initial shape with asnap motion, thereby causing re-engagement of the contact members.

The base 14 of the thermostatic switch is disposed between lugs 31, 32,33 and 34 that are integral with a resilient clamping and supportingmember 35. The member 35 is provided with extensions 36 and 37 havingportions 38 and 39 extending laterally therefrom. The laterallyextending portions 38 and 39 are disposed to rest on the upper face ofthe rim portion of the closure member 9, they clamping member beingprovided with screws 41 for securing it to the rim thereof.

One terminal of the tubular heating element 12 is connected, by acondctor 43, to the terminal 22 of the thermostatic switch,

' and the terminal 23 thereof is connected,

by a conductor 44, to a manually-operable snap switch 45. The otherterminal of the tubular heating element 12 is connected, by a conductor46, to the snap switch 45.

The snap switch 45 is supported by a resilient bracket 47 that issecured to the edge of the rim portion of the closure member 9. Theterminals of the tubular heating element and the conductor leading fromthe thermostatic switch to the snap switch 45, maybe enclosed by a cover48 which is secured to the bracket 47. Electrical connectionmay be madeto the snap switch from a source of electromotive force, by means ofconductors located in a conduit 49 that extends through one wall of thecover 48.

Assuming that the tank 4 contains a sufliamass? cient quantity of waterso that the level thereof is above the pipe 3, and assuming also thatthe tubular heating element 12 is connected to a source of electromotiveforce, fluid contained within the conduit 8 and the pipe fitting 1 willbe heated by the heating element. The heating of the fluid will cause itto circulate from the tank through pipe 5, upwardly through the conduit8, through the pipe 3 and into the tank 4. So long as the tubularheating element is energized, the fluid will'continue to circulate, in amanner well known in the art, until the temperature of the fluid passingthrough the conduit 8 and about the cup portion of the closure member 9,will have reached a temperature of a predetermined value. At thistemperature, the thermostatic switch will operate to 'deenergize theheating element 12.

When the temperature of the fluid has fallen to a predetermined value,the thermostatic switch will operate to reenergize the heating element.In the event that the level of the fluid falls below that of the pipe 3,or in the event that no fluid remains about the heating element 12,andthe heating elements are connected to a source of electromotiveforce, the closure member 9 will be heated to the temperature at whichthe thermostatic switch 13 effects deenergization of the tubular heatingelement 12 in a relatively short period of time, thereby preventing thet-ubular heating element from reaching an excessive or injurioustemperature.

It is to be seen from the drawings that, since the cup portion of theclosure member 9 extends into the pipe fitting 1 and since the tubularheating element 12 is in direct thermal contact therewith, thethermostatic switch will function both to protect the heating element 12in the event no fluid circulates about the heating element and tocontrol the temperature of the fluid circulating thereabout when thelevel of the fluid in the tank 4 is above that of the pipe 3.

Since the thermostatic switch, the tubular heating element 12 and theclosure member may be manufactured as a single compact unit, the heatingelement ma be withdrawn from the conduit 8 easily an quickly by removingthe bolts 11 after the cover 48 has been removed from the supportingbracket 47. Thus, the heating element 12 may be repaired or replacedwith facility.

Various modifications may be made in the device embodying my inventionwithout departing from the spirit and scope thereof. I desire,therefore, that only such limitations shall be placed thereon as areimposed by the prior art and the appended claims.

I claim as my invention:

1. In a fluid heater, the combination with a conduit having inlet andoutlet ports, a heating element disposed in said conduit, and athermostatic switch for controlling said heating element, of a closuremember having a portion of cup-shape extending into said conduit forsupporting said heating element and thermostatic switch in thermalrelation with each other, said thermostatic switch being disposedyin theportion of cup shape.

2. A thermostatically controlled heating unit adapted to be inserted ina conduit of a fluid-circulating system, comprising a closure member ofsubstantially cup-shape for a conduit, a sheathed electric heatingelement extending through the rim and along the walls of said member ofcup-shape, a portion of said heatin element having intimate thermalcontact wlth said closure member, and a. thermostaticcircuit-controlling device disposed in the cup of-said closure member inthermal relation therewith for controlling the energization of saidelement.

3. The combination with a pipe fitting having inlet and outlet ports andadapted to be connected in fluid-circulating system, of a closure memberof substantially cup-shape for said pipe fitting, a tubular heating eement supported by said closure member and in thermal conductiverelation therewith, and a thermostatic switch located in the cup portionof said closure member.

4. The combination with a pipe fitting having inlet and outlet ports andadapted to be connected in fluid-circulating system, of a closure memberof substantially cup-she for said pipe fitting, a tubular heating ementsupported by said closure member and in thermal conductive relationtherewith, a resilient clamping member disposed in the cup portion ofsaid closure member and secured thereto, and a thermostatic switchlocated in said cup portion and supported therein by said clampingmember.

5. A. fluid heater comprising a conduit, a closure member for one endthereof, a sheathed heating element having the ends thereof integrallysecured to said closure member, and a thermostat mounted on said closuremember in thermal communication therewith for controlling said heatingelement in accordance with the temperature of said closure member. v

6. A fluid heater comprising a su port adapted to close an opening in aflui container, an enclosed heating element havin the terminal endsthereof integrally secure to the support, said heating element beinglocated within the casing when said opening is closed by the support,and a thermostat mounted on said support in thermal communicationtherewith for controlling said heating element in accordance with thetemperature of said support, said thermostat being located on theoutside of the easing when the opening is closed by said support.

In testimony whereof, I have hereunto subscribed my name this 10 day ofOct. 1927.

VICTOR G. VAUGHAN.

